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Preterm infants have language development difficulties

MedWire News: Children who are born early are at higher risk for language development difficulties than those born at term, suggest findings from a systematic review and meta-analysis.

Writing in Pediatrics, the researchers report that preterm (born <37 weeks gestation) children scored significantly lower on both simple and complex language tests throughout childhood, even after adjusting for major disabilities and socioeconomic status (SES).

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Previous studies have shown increases in language function problems in children born preterm, but it is less clear whether these problems get better, worse, or remain stable over time, say Inge van Noort-van der Spek (Erasmus University, Rotterdam, the Netherlands) and colleagues.

To investigate, they searched the literature for studies published between 1995 and 2011 investigating language function in preterm born children.

Other inclusion criteria for studies were being published in an English-language, peer reviewed journal; use of a reliable and validated language function test with mean or median values reported; use of a case-control design to minimize bias; and being of sufficient quality as measured by the Newcastle-Ottawa Scale.

In addition, studies were only included in the analysis if the language tests they used were used in at least five studies in total to ensure stability of the results.

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In all, 17 studies met all the criteria. These included a total of 1529 preterm-born children and 945 term-born children. The children had been language function tested between the ages of 3 and 12 years using the Peabody Picture Vocabulary Test (PPVT; simple language function test) and the Clinical Evaluation of Language Fundamentals (CELF; complex language function test) questionnaire.

Van Noort-van der Spek and team found that children born preterm scored significantly lower on both the PPVT and CELF tests, with a combined effect size of -0.45 and -0.62, respectively.

These between-group differences remained significant even after adjustment for potential confounders, such as presence of severe disability and SES.

Notably, the difference in scores between preterm- and term-born children on the CELF questionnaire, but not the PPVT, increased significantly between the ages of 3 and 12 years.

"Absence of language disabilities or amelioration of skills could be interpreted as evidence of neural and functional plasticity in response to early brain damage," say the authors.

"Conversely, the presence of deficits in complex language functions could be an indication that the plasticity of the developing brain is limited," they add. "However, it has been demonstrated that experience and learning can bring a positive change in corticocortical white matter tracts in children with reading problems."

The researchers suggest that longitudinal studies should improve knowledge of this further.